1. Field of the Invention
The invention relates generally to man-made composite building components and their method of manufacture and assembly. More particularly, the invention relates to the production of composite framing members and integrated components such as studs, walls, roofs, floors, and posts.
2. Description of Related Technology
In conventional building construction, building components such as walls, roofs, floors, and posts may be assembled from wooden framing members and sheathing. Framing members, e.g., lumber, may be produced from natural wood cut in standard sizes from trees such as aspen, spruce, pine, and fir. Sheathing, typically made of plywood or oriented strandboard (OSB), is fastened to the frame of a building component using mechanical fasteners and adhesives such as staples, nails, glue, screws or a urethane foam adhesive.
Traditional lumber produced from natural wood generally has shortcomings in consistency, availability, and cost. Likewise, building components made from traditional materials also have shortcomings in consistency, cost, and ease of assembly.
Conventional lumber from natural wood varies widely in quality. Because framing members, such as nominal 2xc3x974s (actually measuring approximately 1xc2xd inches by approximately 3xc2xd inches), are cut whole from trees or logs as solid pieces, they can possess faults inherent in natural wood, such as knots and splits. Knots typically result in reduced strength in a piece of lumber, requiring a high design safety factor leading to inefficient use of materials. In addition, in a condition known as xe2x80x9cwaning,xe2x80x9d lumber cut from an outer surface of a tree, particularly from younger, smaller trees, can exhibit an undesirable rounded, rather than squared, edge. Also, subsequent to milling, lumber can take on moisture or dry out, which causes a board to become warped and unusable for its intended purpose. These faults contribute to 30-35% of conventional lumber being of a downgraded quality rating.
The lumber that remains suitable for use in construction must often be trimmed, shimmed, nailed to fit, or otherwise adapted for use due to inconsistencies in dimensional accuracy. Furthermore, once installed, lumber is subject to dimensional instability due to environmental factors or the other factors mentioned above. For example, in a condition known as nail pop, installed lumber dries out and shrinks, causing fasteners to move or break loose. Likewise, accidental contact with water or moisture can cause wood to swell and permanently warp.
Natural wood used to produce lumber also is becoming more and more scarce, especially in larger sizes, due to the depletion of old growth forests. This scarcity naturally leads to reduction in quality and/or to the rising cost of conventional lumber and of the homes and businesses built with lumber.
This application also relates to cellulosic, composite-articles. One type of composite article is a wood composite such as a man-made board of bonded wood elements and/or lignocellulosic materials, commonly referred to in the art by the following exemplary terms: fiberboards such as hardboard, medium density fiberboard, and softboard; chipboards such as particleboard, waferboard, strandboard, OSB, and plywood. Wood composites also include man-made boards comprising combinations of these materials.
Many different methods of manufacturing OSB are known in the art, such as, for example, those described in Chapter 4.3 of the Wood Reference Handbook, published by the Canadian Wood Council, and The Complete Manual of Woodworking, by Albert Jackson, David Day and Simon Jennings, the disclosures of which are hereby incorporated herein by reference.
The first step in producing a wood composite is to obtain and sort the logs, which may be aspen, balsam fir, beech, birch, cedar, elm, locust, maple, oak, pine, poplar, spruce, or combinations thereof. The logs may be soaked in hot water ponds to soften the wood for debarking. Once debarked, the logs are then machined into strands by mechanical cutting means. The strands thus produced are stored in wet bins prior to drying. Once dried to a consistent moisture content, the strands are generally screened to reduce the amount of fine particles present. The strands, sometimes referred to as the filler material, are then mixed in a blending operation, adding a resin binder, wax, and any desired performance-enhancing additives to form the composite raw material, sometimes called the furnish. The resin-coated or resin-sprayed strands then are deposited onto a forming line, which arranges the strands to form a loosely felted mat. The mat thus formed also can be referred to as an array of strands. The mat, including one or more layers of strands arranged with a selected orientation (including, for example, a random orientation), is then conveyed into a press. The press consolidates the mat under heat and pressure, polymerizing the resin and binding the strands together to form a consolidated array of strands with other additives, including the binder. The boards are then conveyed out of press into sawing operations which trim the boards to size.
It is an object of the invention to overcome one or more of the problems described above.
Accordingly, one aspect of the invention is a composite building component that includes a non-planar molded composite web having two outer zones and two angled zones wherein the caliper of the angled zones differs from the caliper of at least one of the outer zones, and a flange disposed on an outer surface of an outer zone.
Another aspect of the invention is a composite building component including a web having at least one channel defined by a first outer zone, a second outer zone, and at least two angled zones, each of the zones having a caliper, and each of the zones having inner and outer surfaces; a first flange joined to the web at an outer surface of the first outer zone; a second flange joined to the web at an outer surface of the second outer zone; wherein the width of the building component, measured in a direction parallel to a channel, is not greater than the thickness of the building component, said thickness measured as a distance between parallel outer surfaces of the flanges.
Still another aspect of the invention is a composite building component including a non-planar, molded array of wood strands defining a web panel having a caliper and having first and second undulating principal surfaces, the surfaces providing an alternating pattern of first and second sets of ridges extending parallel to each other and oppositely disposed with respect to a center line of the web panel, adjacent ones of the ridges in the first set being connected to intermediate ones of the ridges in the second set by sloped walls, and the caliper of the web panel between the first and second principal surfaces being different in the vicinity of at least one of the first and second sets of ridges as compared to the sloped walls.
Yet another aspect of the invention is a method of producing a composite building component including the steps of: (a) forming a mat including a wood-based material; (b) providing the mat in a die set, the die set having a non-planar configuration with at least two outer zones and at least two angled zones; (c) closing the die to form a die gap, wherein the die gap in at at least one of the outer zones differs from the die gap at the angled zones; (d) consolidating the mat under pressure and heat to form a molded composite web; and (e) joining the web with at least one flange, to form the composite building component.
A further aspect of the invention is a method of producing a building component including the steps of: (a) forming a mat including an array of wood strands; (b) providing the mat in a die set, the die set having a non-planar configuration with first and second die surfaces; (c) closing the die to form a die gap, wherein the die gap provides an alternating pattern of first and second sets of ridges extending parallel to each other and oppositely disposed with respect to a center line of the die set, wherein adjacent ones of said ridges in the first set are connected to intermediate ones of the ridges in the second set by sloped walls formed by the die gap, and wherein the die gap between the first and second die surfaces is different in the vicinity of at least one of the ridges as compared to the sloped walls; (d) consolidating the mat under pressure and heat to form a molded composite web panel; and (e) joining the web with at least one flange, to form the composite building component.
Other objects and advantages of the invention may become apparent to those skilled in the art from a review of the following detailed description, taken in conjunction with the drawings and the appended claims. While the invention is susceptible of embodiments in various forms, described hereinafter are specific embodiments of the invention with the understanding that the disclosure is illustrative, and is not intended to limit the invention to the specific embodiments described herein.